Moved middleware up to actions

[pavelgj]

Action now have middleware support. Removed models specific implementation, models now use common middleware.

Ex:

    const act = action({
      name: 'foo',
      inputSchema: z.string(),
      outputSchema: z.number(),
      use: [
        async (input, next) => await next(input + 'middle1') + 1,
        async (input, next) => await next(input + 'middle2') + 2,
      ]
    }, async (input) => {
      return input.length
    });

[MichaelDoyle]

Thanks, Pavel! 🤙🏼 ✨

[mbleigh]

I've been meaning to revive this for weeks, thanks Pavel! ❤️